Conventionally, a method is disclosed which is configured to: compare an engine rotational speed with a clutch input rotational speed when a vehicle start clutch is engaged gradually; and learn as a torque transmission point a clutch supply hydraulic pressure when the clutch input rotational speed falls by a predetermined rotational speed with respect to the engine rotational speed (see a patent document 1, for example).
A lockup clutch provided in a torque converter is also required to strike a balance between quick engagement for enhancement of fuel efficiency and suppression of driver's uncomfortable feel due to change of vehicle behavior at engagement. For solution, it is conceivable that a torque transmission point of the lockup clutch is also learned, and the learning control for the vehicle start clutch is applied to the lockup clutch.
However, if for ensuring the frequency of learning, the learning control for the torque transmission point of the lockup clutch is performed while the vehicle is running, it is possible that the engine rotational speed is changed by a factor other than the state of engagement of the lockup clutch, causing erroneous learning. The erroneous learning may cause a problem that the lockup clutch is rapidly engaged to change the vehicle behavior and cause a driver to feel uncomfortable.
The present invention is made with attention to the problem described above, and is targeted for providing a vehicular lockup clutch control device and a vehicular lockup clutch control method capable of suppressing an initial pressure, which is supplied to a lockup clutch, from causing a state of capacity excess, when a learning control is performed based on information about a meeting point at which the lockup clutch starts torque transmission.